


Baby, You're Mine

by SailorChibi



Category: Supernatural
Genre: Alternate Universe, Anal Sex, Blow Jobs, Castiel Winchester - Freeform, Castiel is a Winchester, Deep Throating, Destiel - Freeform, Fluff, Human Castiel, Incest, M/M, Non-Hunter Winchesters, Non-hunter au, Possessive Dean, Premature Ejaculation, Student!Cas, Student!Dean, bossy cas, brotherly incest, embarrassed Cas, talk of parents fighting, teenaged cas
Language: English
Status: Completed
Published: 2014-07-19
Updated: 2014-07-19
Packaged: 2018-02-09 11:37:13
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,416
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1981485
Author URL: https://archiveofourown.org/users/SailorChibi/pseuds/SailorChibi
Summary: <blockquote class="userstuff">
              <p>"Baby, I think we're too old to sleep together," he mumbles without opening his eyes.</p><p>"Really?" Cas says, breath washing over Dean's belly, and two fingers hook into the waistband of his boxers. "Cause I thought maybe I'm just old enough."</p>
            </blockquote>





	Baby, You're Mine

Planes and flying have never been Dean's thing. He spends the whole flight digging his nails into the arms of the seat and only breathes again when the wheels hit the landing strip and he's safe on the ground again. He waits a couple minutes before he makes any attempt to leave the plane, ostensibly to allow everyone else off first but really just to give his legs a chance to stop trembling. Only once he feels certain that his legs won't collapse under his weight does he get up.

He's traveling light, just a duffel bag, so he doesn't need to wait for luggage. And that's a good thing, cause it's been so long since he last saw his family that he's overeager now. He heads for the airport, scanning the crowds. He knows Sammy won't be here - no, the little bitch decided his Spring break was better spent in Stanford making time with his hot new girlfriend - but his mom and dad and Cas are a different story. 

"Dean!"

Dean half-turns at the shout and nearly gets knocked off his feet by about a hundred and forty pounds of teenage boy. He laughs and drops his duffel, wrapping his arms around Cas and lifting the kid up. "Hey baby," he says into the messy dark brown hair, grinning when he hears Cas grunt a protest.

"Don't call me that, Dean, I'm not a baby anymore."

"No?" Dean says, the teasing grin on his face disappearing quickly when he gets his first real look at his youngest brother. Holy shit, Cas isn't kidding. Somehow, in the two years since Dean's seen him, he's shot up a good three inches and filled out in all the right places. The little bit of scruff on his chin looks good, drawing attention to the enormous blue eyes, and the t-shirt and jeans he's got on leave very little to the imagination. Dean ends up swallowing hard instead of making a comment. 

"I'm 5'10 now," Cas says proudly.

"Still gotta catch up to me, never mind Sammy," Dean says finally, glad that at least some part of his brain is still working right. Because it's definitely not right that he wants to pin his little brother to the ground and lick him all over, strip him of those too tight clothes and see if that dusky tan is everywhere or if he's pale underneath his clothing.

"Dean!" Mary catches up to them before Cas can respond, and Dean sweeps her into an enthusiastic hug that makes her laugh. She ruffles his hair and Cas beams at them both, grabbing Dean's duffel and slinging it over one thin shoulder.

"Where's Dad?" Dean asks, realizing his father isn't around.

"He had to work. He wanted to be here, but -" Mary looks a little anxious.

"It's cool, Mom, I get it." Dean wraps an arm around her waist. It's been so long since he's seen his mom, he can't imagine giving her a hard time over something so stupid. He's got two whole weeks and he's gonna make the most of them.

The three of them walk towards the exit, and though Dean answers all of the questions that are being thrown at him he can't stop sneaking peeks at Cas. Damn but the kid grew up hot. He can't help wondering if Cas has a girlfriend, or maybe even a boyfriend. The thought makes him scowl. Cas is too good for any of the idiots from Lawrence. He deserves better.

Like, say, a college student who's majoring in Engineering while working full time at the most popular mechanics shop this side of LA?

No. God no. Behave, Dean tells himself firmly. Cas is his little brother and that's wrong. Bad. It doesn't matter how gorgeous he is, or how good it feels when Cas tucks himself under Dean's arm and hangs off of him the way he always did when they were kids. It doesn't matter that Cas whines until Dean gets into the back with him and then sits so close he's practically in Dean's lap. It definitely doesn't matter that Cas spends the whole ride with his pink lips about two inches away from Dean's face, and the only thing that Dean can think about is how they'd look around his cock.

Jesus this is going to be a _long_ two weeks.

It gets a little easier once they're home and Mary recruits them both into helping make supper. John comes trundling in a couple hours later and they all sit down together, and it's a little weird without Sammy but mostly it's just awesome to be home again. Dean stuffs himself with fried chicken and three pieces of apple pie with ice cream and sprawls out on the sofa afterwards, groaning because his jeans are too tight. 

"Dean," Mary says, "You're going to have to share a room with Cas while you're here. Is that okay?"

"How come?" Dean asks, because he's like 90% sure he'll be dreaming about Cas tonight as it is without sleeping three feet away from him.

"You know your father and I need to get the roof replaced. The water damage is spreading and your room is just a mess now." Mary shakes her head, her lips thinning, and on the floor in front of the couch Cas shrinks down a little.

Dean says quick, "That's fine, Mom, really. I don't mind."

"Are you sure?"

"Nope. Kid and I'll be fine." He drops a hand on Cas' head like he's gonna mess up his hair, but when Mary nods and walks away he lets his hand slide down to Cas' neck and squeezes gently. "They been arguing again?"

Cas nods, just once, and his blue eyes look even brighter now. Shit. Dean squeezes again and rubs hard, because he knows Cas hates it when their parents fight. Always has. And now he's alone here most of the time 'cause Sammy's gone too. Not for the first time Dean feels a pang of guilt over having left, only his mom's so damn proud that he's making it on his own he can't come back now even if he wanted to.

"You know, baby," he rumbles low, "you can come stay with me this summer if you want."

"Really?" Cas' deep voice quivers a little.

"Sure. You'll have graduated, I got room. You're my little brother. You wanna come live with me, all you gotta do is say so." 

Cas turns and presses his face into Dean's chest. "Thanks Dean."

"S'nothing," Dean mutters, embarrassed, and rubs a hand up and down Cas' back until he stops shaking. He didn't know it was this bad, but maybe it's not a surprise. Makes him mad, though. Cas doesn't deserve to go through this alone. He feels bad now for not making the offer sooner, but honestly he hadn't thought Cas or Sammy would want to.

For a little while, right up until they go to bed, he's just Dean's baby brother that Dean wants to take care of. And that doesn't change even after the door is shut and the lights go off. He just starts wanting to take care of Cas in a totally different way. A very inappropriate way. Especially when Cas strips down to his boxers and sits on the bed, close enough to the edge that he could easily slide to his knees and - and holy shit Dean's dick is going from half hard to cut glass in about thirty seconds.

He makes himself turn away, strips down to his own boxers and gets into Sammy's bed. It feels good and he gives a little wiggle, sighs and shuts his eyes.

The mattress sinks down with another weight less than a minute later.

"Baby, I think we're too old to sleep together," he mumbles without opening his eyes.

"Really?" Cas says, breath washing over Dean's belly, and two fingers hook into the waistband of his boxers. "Cause I thought maybe I'm just old enough."

Dean's eyes pop open immediately, but all protests catch in his throat with a strangled moan when Cas unceremoniously yanks his boxers down and swallows him. His chin bumps against Dean's balls and Dean chokes, fingers scrabbling at the sheets in surprised arousal. 

"Jesus fucking Christ," he gasps out finally, mind pretty much shorting out in pleasure. He's never had anyone who could take him this deep and it's like sin, hot and wet and sweet.

Cas giggles around him and that makes it even better, Dean's hips shifting before he can stop himself, but Cas is already sliding up. His blue eyes are glittering with mischief, a smirk on his swollen lips. "I've missed you, Dean," he says.

"Cas," Dean says weakly. Because he's a strong man, all things considered, but this is temptation on a fucking silver platter and it gets no easier to resist when Cas shimmies out of his boxers. He's tanned from head to toe with pink nipples and a pretty cock, and the way he moans when he wraps his fingers around his dick snaps the last of Dean's control.

He's swinging them around before his mind even registers the move, pushing Cas down into the mattress and pinning his wrists easily. Cas blinks up at him, looking shocked, and Dean growls as he sinks down and kisses him open. 

"Little tease," he grits out between nips at Cas' bottom lip. "Maybe I should start callin' you that instead of baby, what d'you think."

"Dean," Cas whines. "Please."

"You're my brother, Cas. It's not right."

"Why not? I've never wanted anyone but you," Cas says, so earnest that Dean has to believe him. "I waited for you, Dean."

"Then where'd you learn to suck cock like that?"

Cas actually blushes a little. "I, um, ordered a toy. To practice."

The mental image Dean comes up with is so hot he can't handle it. He kisses Cas again, licking him open slow and wet until Cas is squirming and mewling beneath him, trying to buck up to get more friction. Dean keeps his wrists pinned to the bed with one hand and uses the other to shove his boxers down until he can kick them off. They're both naked and the heat is incredible.

"You been dreaming about me, baby boy?" he whispers, kissing the side of Cas' throat and rolling his hips, making the contact deliciously fleeting. "Dreaming about your big brother coming home and fucking you? No one else would take care of you the way that I can, you know. Been caring for you since you were a kid." He noses at Cas' face, tastes tears on Cas' cheeks. "You're my baby. My baby brother."

"Dean." It seems to be the only thing Cas is capable of saying. " _Dean_."

"Shh, I know, but you don't want Mom and Dad to hear. Gotta be quiet, my good boy." He kisses Cas again, lets Cas in as he starts rubbing their bodies together. Cas jerks against him with a muffled sound, his body trembling, and Dean breathes out as he feels wet heat spreading between their bellies. Cas looks mortified and Dean can't help grinning.

"S-sorry, I didn't -"

"Shh, baby. Quiet." Dean slides his knee up, between Cas' thighs, and settles between nice and easy. Cas is relaxed now and Dean grabs the lube out of his duffel, sliding a slicked up finger inside of him carefully. He starts off slow, not wanting to run the risk of hurting his little brother, knows that they've got a little time before Cas is worked up again. 

He fingers Cas open, one two three, until tears come to Cas' eyes again, until he's squirming and pleading and begging so pretty Dean wants to have this forever. He rubs his fingers over Cas' sweet spot just to see those baby blues flutter and hear the gravelly voice jump, chuckles and mouths at Cas' throat and collarbone until Cas gets impatient and slaps at his chest.

"C'mon, Dean," he orders, pouting. "Fuck me."

"Always were a bossy little brat," Dean mutters, but he's grinning again, easing his fingers out and gripping Cas' ass to line himself up. He's careful as he pushes in, 'cause this is Cas and he'd rather cut off his own dick than hurt him. Cas wiggles impatiently and claws red scratches into Dean's shoulders, frustrated at the pace, until Dean bottoms out and he ends up clinging to him instead.

Dean soothes him, brushes little touches down his back and across his chest, laves attention on his nipples until Cas loosens up. Only then does he start to fuck him, gentle at first until he can't help but just take what he wants, deep and hard, until Cas is biting his lip raw to keep from screaming and Dean is vowing that someday they'll do this where he can hear every sound he can wring out of Cas' body.

"Gonna come for me, baby?" he gasps out, pounding Cas so hard that Cas is sliding across the sheets. He frees a hand to grab Cas' dick, pumping it fast. "My good boy, I'm gonna take care of you. Let's see it, sweetheart, I wanna see, Cas, lemme see."

"Dean," Cas mouths, seizing up so tight that Dean comes immediately. He keeps his eyes open and locked on Cas, still rocking into him, memorizing the way his lips part and his whole body starts to shake. It's the hottest thing Dean's ever seen and he immediately wants to see it again, as often as he can in every way his filthy mind can come up with.

"Fuck," he breathes out, slumping against his brother.

"Heavy," Cas mumbles finally, pushing at him, and Dean obligingly slips out and rolls over. He doesn't need to look to know there's a screwed up look of disgust on Cas' face, and he gropes around for a t-shirt and makes a half-decent attempt at wiping them both off. 

Apparently pleased by this, Cas scoots closer until he can slot himself neatly into Dean's arms. Dean tucks him close, resting his cheek on Cas' head in a way that's so natural it just _is_. "You graduate in three more months, baby," he says into Cas' messy hair, and for once the sexy bedhead look is because he actually did get laid. "I'mma come home and get you."

"You better," Cas says around a sleepy yawn. "I'll hold you to it."

**Author's Note:**

> Come visit me on [tumblr](http://tsuki-chibi.tumblr.com/).


End file.
